Chemical dispensing system

ABSTRACT

Vertical stacks of tablets are stored in a cartridge that removably fits into a swimming pool dispenser housing. A battery is disposed in the cartridge, a motor for driving a tablet dispensing foot is disposed in the housing, and an electrical connection between the battery and the motor is established when the cartridge is inserted in the housing. The electrical connection is formed by coaxial conductors around which the foot rotates to engage the bottom tablet of each stack in turn, sliding it out from the rest of the stack and allowing it to drop from the dispenser into the pool. The electrical connection from the battery to the motor and the engagement of the foot are automatically severed and established without component damage when the cartridge is removed and inserted, respectively. A universal bracket permits the housing to be mounted on the pool edge whether it is a horizontal surface, or a bull nose coping tile, while maintaining the housing vertical so the force of gravity can be most effectively used to deliver the tablets to the water surface.

United States Patent [191 Rowlette [451 Nov. 11, 1975 CHEMICALDISPENSING SYSTEM John J. Rowlette, Arcadia, Calif.

[73] Assignee: Duane D. Erway, Rochester, NY.

a part interest [22] Filed: Feb. 22, 1974 [21] Appl. N0.: 444,826

[75] Inventor:

Primary E.\'aminerStanley 1-1. Tollberg Attorney; Agent, orFirmChristie, Parker & Hale [57] ABSTRACT Vertical stacks of tablets arestored in a cartridge that removably fits into a swimming pool dispenserhousing. A battery is disposed in the cartridge, a motor for driving atablet dispensing foot is disposed in the housing, and an electricalconnection between the battery and the motor is established when thecartridge is inserted in the housing. The electrical connection isformed by coaxial conductors around which the foot rotates to engage thebottom tablet of each stack in turn, sliding it out from the rest of thestack and allowing it to drop from the dispenser into the pool. Theelectrical connection from the battery to the motor and the engagementof the foot are automatically severed and established without componentdamage when the cartridge is removed and inserted, respectively. Auniversal bracket permits the housing to be mounted on the pool edgewhether it is a horizontal surface, or a bull nose coping tile, whilemaintaining the housing vertical so the force of gravity can be mosteffectively used to deliver the tablets to the water surface.

30 Claims, 9 Drawing Figures US. Patent Nov. 11, 1975 Sheet 1 of33,918,607

U.S. Patent Nov. 11, 1975 Sheet 2 013 U.S. Patent Nov. 11 1975 Sheet 3013 3,918,607

. a $15 a CHEMICAL DISPENSING SYSTEM 7 I BACKGROUND or THE INVENTION"This invention relates to a chemical dispensing system and, moreparticularly,- tosuch asystem that is well suited to dispense a waterevaporation retardant in tablet form at relatively constant intervalsover a long time period upon the water surface of swimming pools, ponds,reservoirs or other bodies of water.

My US. Pat. No. 3,531,239, which issued Sept. 29,

. 1970, discloses a water evaporation retardant that can be applied to awatersurface in tablet form, as well as other solid forms. A largepercentage of heat loss from the water in a swimming'pool is caused byevaporation. Therefore, the use of a water evaporation retardant cangreatly decrease the cost of heating the pool and even increase thewater temperature in the absence of heating It has been found that theevaoporation retardant SUMMARY OF THE INVENTION According. to theinvention, a chemical dispensing system has a cartridge for storingtablets of a chemical, particularly a water evaoporation retardant, inparallel passages and a dispenser housing into which the cartridgeremovably fits. The housing contains a tablet dispensing assembly thatengages the cartridge and an electrical clock motor that drives thedispensing assembly to sequentially deliver tablets from the cartridgeto the water at relatively constant intervals over a long period oftime, I

A feature of the invention is the provision of a battery in thecartridge, and an electrical connection from the battery to the motor toprovide power thereto. When a cartridge is removed from and insertedinto the dispenser housing, the electrical connection is severed andestablished, respectively, without damaging any of the components ofthesystem. Preferably, the electrical connection comprises coaxialconductors aligned with acentral axis along which the battery and motorlie.

Another feature of the invention is the storage of the tablets inparallel vertical stacks arrangedin a circle about-thecentral axis ofthe system inside a cartridge that removably fits into the dispenserhousing from Responsive to the motor, the tablet at the. bottom of eachstack is freed in sequence to fall through the passageway to the exit. II a I Another feature of the invention is the provision of a tabletdispensing foot that rides along the stacks of tablets at the level ofthe bottom tablet in each.stack.. The stacks are held up by tabletretaining protrusions, such that the bottom tablet in each stack liescompletely below the main body of the cartridge, and the second tabletfrom the bottom in each stack lies partially in its tablet storagepassage. Preferably, the foot partially overlies one of the protrusions,and is connected by a slim post, which extends between the protrusions,to a driving shaft; the driving shaft'fits around the coaxialconductors, and is coupled by a great train to the motor. The post isvertically movable and is urged by a spring in an upward directiontoward the cartridge. As a result, the foot is temporarily depressedbelow the level of the bottom tablet in the stacks when the cartridge isoriented so the protrusions lie above the foot during cartridgeinsertion. The foot is attached to the slim post by a hinge that permitsthe foot to rotate and slide out between the protrusions as thecartrdige is removed, should the foot have traveled to a position undera stack.

Another feature of the invention is a universal bracke't assembly thatpermits the dispenser housing to be mounted in a vertical position atthe edge of a swimming pool whether it be a horizontal surface or a bullnose coping tile. A lower angular member is fixedly attached to the edgeof the pool. The dispenser housing is pivotably attached to an upperannular member. The

upper member is adjustably attached to i the lower member such that thedispenser housing pivots to a vertical position in abutment with thevertical side of the lower angular member.

In the preferred embodiment, the cartridge has a cylindrical bodyportion aligned with the central axis of the system when in position inthe housing. The body portion has a plurality of parallel passagesarranged in a circle about the central axis, in which the stacks oftablets are stored, and a center passage on the central axis in whichthe battery is located. At the bottom of the cartridge, an inner ringand an outer ring define an annular channel in which the tabletdispensing foot moves under the tablet storage passages at the level ofthe bottom tablet in each stack. The tablet retaining protrusions areformed at intervals along the rings aligned with the stacks of tablets.

BRIEF DESCRIPTION OF THE DRAWINGS The features of a specific embodimentof the best mode contemplated of carrying out the invention areillustrated in the drawings, in which:

FIG. 1 is a side sectional view of a swimming pool chemical dispensingsystem incorporating the principles of the'invention;

FIG. 2 is a sectional view of the swimming pool chemical dispensingsystem taken along line 22 in FIG. 1;

FIG. 3 is a sectional view of the system taken along line 33 in FIG. 1;

FIG. 4 is a side sectional view of the center post assembly of thesystem;

FIG. 5 is a side, partially sectional view of the tablet dispensingassembly of the system;

FIG. 5A is a front view of part of the dispensing assembly taken alongline 5A-5A in FIG. 5;

FIG. 5B is a side view of part of the dispensing assembly when thedispensing foot is rotated out of operating position;

FIG. 6 is an exploded side elevation view of the mounting bracket forthe swimming pool chemical dispensing system; and

FIG. 7 is a top plan view of the mounting bracket of FIG; 6.

DETAILED DESCRIPTION OF THE SPECIFIC EMBODIMENT In FIG. 1 there is showna swimming pool chemical dispensing system comprising a permanentdispenser housing 10, an expendable chemical storage cartridge 11 thatremovably fits into housing 10, and a permanent lid 12. As disclosed inmore detail below in connection with FIGS. 6 and 7, the system issupported above the water surface of the swimming pool with approximatealignment of its vertical axis 13.

A cylindrical body 14 of cartridge 11 has a center passage aligned withaxis 13 and a plurality, e.g., eight, of passages 16 arranged in acircle around passage 15. Passage 15 and passages 16 are parallel toeach other and vertical. A swimming pool chemical in the form of tabletsis stored in passages 16 in stacks 20. It is convenient to mold body 14from styrofoam. If the body 14 is fabricated by molding, it isadvantageous for good mold release to form passages 16 with a draft; butit is also desirable to maintain a relatively close fit between thetablets and passages 16 to prevent lateral movement of the tabletsduring storage and transportation. To satisfy both these considerations,as illustrated in FIG. 1, the diameter of passages 16 tapers down fromtop to bottom, and three or more ribs 17 are formed along the length ofpassage 16. Ribs 17 also taper down from the top of passages 16, wheretheir protrusion into passage 16 is large, to the bottom thereof, wheretheir protrusion is small, so that the effective diameter of passages 16is the same throughout their length. In other words, ribs 17 equalizethe effective diameters of passages 16. The provision of ribs 17 doesnot hinder the release of body 14 from its mold in the course offabrication. The system is specifically designed to dispense anevaporation retardant such as that disclosed in my U.S. Pat. No.3,531,239, which issued September 29, 1970. A conventional dry cellflashlight battery 21, e.g., a D cell, lies in the bottom portion ofpassage 15 with a positive terminal 22 facing downward. A contact 23,which is made of an electrically conductive spring metal, such as brass,extends from a negative terminal 24 of battery 21 to the bottom ofcartridge 11 in the vicinity of positive terminal 22. An inner tabletdispensing ring 25 and an outer tablet dispensing ring 26 are cementedto the bottom of body 14. Rings 25 and 26 form between them an annularchannel 30, slightly wider than the tablets, in which a rotating tabletdispensing foot 68 rides (FIG. 2). Inner ring 25 has an outward tabletretaining protrusion 27 at the bottom edge of channel 30 directly undereach of passages 16. Outer ring 26 has an inward tablet retainingprotrusion 28 at the bottom edge of channel 30 directly under each ofpassages 16. Each of protrusions 27 present a smooth upper surface overwhich dispensing foot 68 traverses. The bottom tablet in each of stacksrests on the corresponding protrusions 27 and 28. Thus, between stacks20 the tablets are free to fall out of channel 30, but directly understacks 20 the tablets are held up by protrusions 27 and 28. A nipple 34(FIG. 2) is formed at the leading edge to the movement of dispensingfoot 68 on the top surface of each of protrusions 28 to preventinadvertant reverse movement of the bottom tablet of each of stacks 20,i.e., movement in the direction opposite to movement of dispensing foot68. As illustrated in FIG. 1, the thickness of rings and 26 is selectedso the bottom tablet in each of stacks 20 lies completely below body 14within channel 30, and about one-half of the second tablet from thebottom in each of the stacks 20 lies below body 14 in channel 30, theother half lying above channel 30 in the corresponding passage 16. Inother words, protrusions 27 and 28 are spaced from the end of body 14 adistance greater than one tablet thickness and less than two tabletthicknesses. The outer periphery of ring 26 has a plurality, e.g., four,of keyways 35. As illustrated in FIG. 1, the tablets of stacks 20 have aclose fit in passages 16, so the tablets remain axially aligned withpas.- sages 16 as they move. Likewise, protrusions 27 and 28 hold thebottom tablet of stacks 20 so they are aligned with passages 16.

A truncated hollow conical body 36 of dispenser housing 10 has aplurality, e.g., eight, of strengthening ribs 37 and 38. A pair ofvertical spaced protrusions 33 are formed outside body 36 for purposesof mounting. Orienting side surfaces 32 on protrusions 33 are paral? lelto axis 13. Underneath ribs 37 are a plurality, e.g., four, ofprotrusions 18 (FIG. 2). A spacer ring 39 has a plurality, e.g., four,of indexing protrusions 40, and a plurality, e.g., four, of recesses 19(FIG. 2) for clasping protrusions 18. Ring 39 is secured to the bottomof ribs 37 by cement. When cartridge 11 fits in the hollowed cavity ofbody 36, as shown in FIG. 1, protrusions 40 engage keyways 35 to fix theangular position of cartridge 11 about axis 13. The bottom of ring 39has a plurality, e.g., four, of mounting columns 41 connected by a thinannular support web 42. FIG. 2 illustrates the proper relative positionof columns 41 and recesses 19 about axis 13. In FIG. 1, columns 41 areshown in alignment with recesses 19 to permit both to be represented ina single section view. A truncated conical tablet deflecting shield 43has a plurality, e.g., four, of mounting extensions 44 (FIG. 3).Fasteners 45 attach mounting extensions 44 to mounting columns 41,thereby securing shield 43 to spacer ring 39. In the annular regionunder channel 30 of cartridge 11, shield 43 presents a downwardly andoutwardly sloping deflecting surface. An electric clock motor is securedby a convertti'onal fastener not shown to a mounting plate 51, which isattached to the bottom of shield 43 by fasteners 52. Clock motor 50 hasan output, i.e., hour, shaft 53, that extends upwardly through anopening in plate 51. A spur gear 54 is mounted at the end of shaft 53above plate 51. Shaft 53 rotates one revolution in twelve hours. Acenter post assembly 55, which is described in more detail below inconnection with FIG. 4, extends along axis 13 from plate 51 to battery21. The bottom of post assembly 55 fits in a bore 56 of plate 51, whereit is secured by cement. Post assembly 55 serves two functions. Thefirst function is to transmit electrical power from battery 21 to plate51, where insulated conductors 57a and 57b, which extend through apassage 58 from bore 56 to the periphery of plate 51, transmit theelectrical power to clock motor 50. The second function is to support arotating tablet dispensing assembly 59, which is described in detailbelow in connection with FIG. 5. Assembly 59 has a bore 60 aligned withaxis 13. Post assembly 55 fits loosely enough in bore 60 so assembly 59is free to rotate around post 55 but not so loose as to introduceappreciable wobble. Around the bottom of assembly 59 is formed a spurgear 61 having teeth that mesh with the teeth of spur gear 54. By way ofexample, the gear ratio could be 1:1. Thus, each time that shaft 53makes one complete revolution, assembly 59 also makes one revolution.

As described in more detail below in connection with FIG. 5, assembly 59carries tablet dispensing foot 68. As assembly 59 rotates. foot 68traverses channel 30 and pushes the bottom tablet in each of stacks 20in turn along channel 30 until such tablet is clear of the correspondingprotrusions 27 and 28, where it is free to fall. While the bottom tabletin one of stacks 20 is being pushed along channel 30, the second tabletfrom the bottom is held in place by the walls of the correspondingpassage 16. After the bottom tablet is clear of protrusions 27 and 28and is thereby dispensed, the second tablet from the bottom slides downagainst protrusions 27 sand 28 to replace It. In this manner, thetablets stored in cartridge 11 are sequentially dispensed one by one asassembly 59 rotates and foot 68 traverses a given path. which iscircular. The dispensed tablets fall by vir tue of gravity until theyhit shield 43 and are deflected outwardly to avoid clock motor 50.

On the bottom of body 36 are mounted an inner funncl 69 and an outerfunnel 70. Funnel 70 is secured to the bottom of body 36 by fasteners71, and funnel 69 is clamped between funnel 70 and the bottom of body36. Funnel 69 has a hole 72 drilled along an axis parallel to and spacedfrom axis 13, and funnel 70 has a hole 73 drilled along an axiscoinciding with axis 13. Holes 72 and 73, which serve as the exit fromthe dispensing system. are large enough to permit the tablets to passwithout difficulty. After the dispensed tablets are deflected outwardlyby shield 43, they fall freely through the annular region around clockmotor 50 until they are deflected by the inwardly and downwardly slopingsurface of funnel 69. At the bottom of funnel 69, the tablets fallthrough hole 72, fall through hole 73, and drop into the water belowdispenser housing 10.

Holes 72 and 73 are intentionally misaligned to minimize the upward flowof water vapor into the interior of body 36. A plurality of small holes74 are drilled through funnel 70 to permit trapped water vapor to escanefrom the region between funnels 69 and 70. If too much water vaporenters the interior of body 36 despite these measures. so the tabletsbecome moist enough to impair their dispensability. more elaboratemeasures can be taken. For example. silica gel could be placed in thefree space of passage lying above battery 24; or a combination ofchemicals that give off ammonia when exposed to water vapor could beplaced inside body 36 below cartridge 11, so the lighter ammoniaoccupies the interior of body 36 where it is effectively trapped andthus prevents the upward movement of the water vapor through holes 72and 73.

Reference is made to FIG. 4 for a detailed description of post assembly55. The bottom ofa hollow electrically conductive tube 80 fits in bore56, where it is secured to plate 5| by cement. By way of example, tube80 could be rendered electrically conductive by nickelplating its outersurface. or it could be made from a conductive material and optionallynickel-plated to reduce corrosion. A spring retaining ring 8] is securedinside tube 80 by cement. An electrically insulative disc 82 is attachedto an electrically conductive disc 83 by cement. By way of example, disc83 could be pure nickel. An insulated. flexible electrical conductor 84extends through the Interior of tube 80. At one end, conductor 84 iselectrically connected to the side oldlsc 83 facing disc 82. At theother end, conductor 84 is electrically connected to conductor 57a. Theouter surface of tube 80 is electrically connected to conductor 57b. Acompression. spring 85 extends between retaining ring 81 and disc 82.Battery 21, positive terminal 22. and contact 23 of cartridge 11 areshown in their positions relative to post assembly 55, as cartridge IIis about to be placed in dispenser housing 10. As cartridge 11, which isnot shown in FIG. 4, moves downwardly, terminal 22 contacts disc 83 andcontact 23 engages the outside surface oftube 80. As depicted by thearrows. battery 21 moves downward, disc 83 moves downward, and contact23 moves outward until cartridge ll bottoms against ring 39 (FIG. 1). Atsuch time. discs 82 and 83 are spaced from the end of tube 80, therebyprovidng leeway for variations in the position of battery 21. The forceof spring 85 insures that good electrical contact is maintained frompositive terminal 22 through disc 83 and conductor 84 to conductor 57a.By virtue of its flexibility. the excess length of conductor 84 coilswithin tube 80. The outward deformation of contact 23 which is caused byits engagement with the outer surface of tube 80, insures that goodelectrical contact is maintained from negative terminal 24 through tube80 to conductor 57b. To improve the corrosion resistance of theelectrical connection, the end ofcontact 23 engaging the outer surfaceof tube 80 could be plated with nickel.

Reference is made to FIGS. 3, 5, 5A, and 5B for a detailed descriptionof tablet dispensing assembly 59. Bore 60 is formed in a central shaftportion 86. At the upper end of shaft portion 86, a crank portion 87extends radially outward. A post 88 fits slidably in a bore 89 at theend of crank portion 87. The diameter of post 88 is smaller than thespace between protrusions 27 and 28. A button 90 is formed on the lowerend of post 88 as a stop to prevent it from sliding upwardly out of bore89. A leaf spring 91, which is secured to crank portion 87 by a rivet92, engages a slot in button 90 and urges post 88 in an upwarddirection. Also. rotation of post 88 is prevented by this engagement.Tablet dispensing foot 68 is attached to the upper end of post 88 by ahinge 93 (FIG. 5A). Foot 68 is free to rotate about hinge 93 in aclockwise direction. from its position as viewed in FIG. 5. A lowersurface 94 of foot 68 is shaped to limit the extent of rotation of foot68. In FIG. 5 foot 68 is represented at the counterclockwise limit ofits rotational path. In FIG. 58, foot 68 is represented at the clockwiselimit of its rotational path. Thus. surface 94 and the adjacent surfaceof post 88 function as a cam and a cam follower to limitthe rotation offoot 68. The center of gravity of foot 68 lies to the left of hinge 9 3,as view in FIG. 5, so gravity urges foot 68 in a counterclockwisedirection to the position depicted in FIG. 5.

If dispenser assembly 59 happens to be oriented so foot 68 lies betweenadjacent stacks 20 when cartridge 11 is inserted into dispenser housing10, foot 68 immediately moves up into channel 30 at the level of thebottom tablets. as shown in FIG. I. In this position, button 90 abutsthe bottom of crank portion 87 and the top of foot 68 lies below thesecond tablet from the bottom of the stack. However, if dispenserassembly 59 happens to be oriented so foot 68 lies under one of stacks20 when cartridge 11 is inserted into dispenser housing 10, protrusions27 and 28 prevent foot 68 from moving upward to the level of the bottomtablets. In such cases, cartridge ll depresses foot 68 downwardly topush post 88 in opposition to the force of spring 91, where is remainsuntil assembly 59 rotates sufficiently for foot 68 to be clear ofprotrusions 27 and 28; then the force of spring 91 urges post 88upwardly until button 90 abuts 7 the bottom of crank portion 87 and foot68 assumes a position at the level of-the bottom tablets.

if dispenser assembly 59 happens to be oriented so foot 68 lies betweenadjacent stacks 20 when cartridge 11 is removed from dispenser housing10, foot 68 is disengaged from channel 30 without touching cartridge 11.However, if dispenser assembly 59 happens to be oriented so foot 68liesunder one of stacks 20 when cartridge 11 is removed, foot 68contacts protrusion 27 as cartridge 11 is removed. Since foot 68 is freeto rotate in a clockwise direction, it slips out of the space betweenprotrusions 27 and 28 and is thereby disengaged from channel 30 withoutbeing damaged.

Since the force of gravity is used to deliver the tablets from cartridge11 to the water, it is important that dispenser housing be orientedso..axis 13 is approximately vertical. A universal bracket assemblyillustrated in F168. 6 and 7 permits dispenser housing 10 to be mountedvertically at pool edges whether the mounting surface is flat or is anyof the variety of bull nose copings with different shapes. A lowerangular member 100 is secured by cement and by two fasteners 101 to aflexible strip 102, which is, in turn, secured by cement to the edge ofthe swimming pool represented at 103. Fasteners 101 each have a headrecessed in strip 102 and are fixed against rotation. For example.member 100 can be made of stainless steel, and a cloth re-inforcedneoprene rubber strip could be used for member 102 to provide thedesired flex without stretching so much that bracket 100 would tipforward under the weight of dispenser housing 10. A portion 100a abutsthe upright side of the pool and a portion 10% lies above the coping. Anupper angular member 104 has a portion 104 a that abuts portion 100b,and is fastened to it by two finger nuts 105, which screw onto fasteners10]. Member 104 also has a portion 104b from which vertical hingemounting plate portions [040 extend. Portion 104a has slots 106 thatpermit the position of member 104 to be adjusted toward or away from thepool edge relative to .nember 100. Hinge mounting plate portions 1040are spaced apart just enough to fit between hinge mounting protrusions33 of body 36. Plate portions 104a and protrusions 33 are joined byfasteners 107, which serve as hinge points, allowing dispenser housing10 to rotate. Thus dispenser housing 10 rotates in a clockwisedirection, as viewed in FIG. 6. until protrusions 33 abut portion 100a.Member 104 is adjusted relative to member 100 until orient ing sidesurfaces 32 are flush with portion 1000. When this adjustment is made.axis 13 ofdispenser housing 10 is vertical, assuming that portion 100aof member 100 is exactly vertical. if this is not the case, then member104 is adjusted accordingly relative to member 100, so dispenser housing10 is vertically oriented. Dispenser housing 10 is free to rotate ineither direction. as viewed in H0. 6, in order to accomplish thisadjustment.

The described swimming pool chemical dispensing system is designed toaccommodate expendable tablet storage cartridges, i.e., cartridge 11.Thus, for example, one cartridge could carry a one month supply oftablets and a battery having sufficient electrical energy storagecapacity to energize the dispenser actuating motor, i.e., clock motor50, for a comparable period of time. Each month, the lid is taken off;the used cartridge is removed upwardly from the dispenser housing,thrown away, and replaced from above with a new cartridge;

and the lid is put back on. As the new cartridge is placed in thedispenser housing, the electrical connection between the battery in thecartridge and the motor in the dispenser housing is automaticallyestablished in the manner described above in connection with FIG. 4.

' tom tablet of each stack in the new cartridge, i.e., positionedinchannel 30, in the manner described above in connection with FIG. 5.Thereafter, the motor drives the actuating mechanism in response to theenergy from the battery so the tablets are dispensed sequentiallyone ata time over the period of a month. When the cartridge is removed at theend of the month, the electrical connection from the battery to themotor is automatically interrupted and the tablet actuating mechanism isdisengaged from the cartridge without damage to the components ofdispenser housing 10.

The described embodiment of the invention is only considered to bepreferred and illustrative of the inventive concept; the scope of theinvention is not to be restricted to such embodiment. Various andnumerous other arrangements may be devised by one skilled in the artwithout departing from the spirit and scope of this invention. Forexample, it may be desirable to automatically disconnect clock 50 duringcertain times. it has been found that during periods of time in whichthe pool is not being used, such as at night, less frequent applicationsof water retardant are required to maintain an effective retarding layeron the water surface. Therefore, it would usually be desirable todisconnect clock 50 at night. This could be done by means of a photocellactuated electrical circuit that switches off clock 50 when the sun goesdown, and switches on clock 50 when the sun comes up. Alternatively,this could be done by a gear train between assembly 59 and shaft 53which disengages during part of each day, e.g.. every other completerevolution of shaft 53. Furthermore, the stacks of tablets in thecartridge could be arranged differently, e.g., in rows, in which casethe given path that the tablet dispensing foot traverses would not becircular. While mounting the battery in the cartridge is most convenientfor the user, it would also be possible to design the dispenser with thebattery in the dispenser, rather than in the cartridge. Further, thetablets could take many sizes and shapes, including what are sometimesregarded as briquettes or pellets, or in general solid compact units.

What is claimed is: l. A swimming pool chemical dispensing systemcomprising:

a cartridge for storing tablets of a swimming pool chemical; a dispenserhousing into which the cartridge removably fits; means for attaching thehousing to the edge of a swimming pool; a battery having a positiveterminal and a negative terminal disposed in the cartridge;

means disposed in the housing including an electrical clock motor fordispensing tablets stored in the cartridge into the swimming poolresponsive to the power source; and means operable when the cartridge ispositioned in the housing for transmitting power from the source to thedispensing means to dispense tablets stored in the cartridge, the powertransmitting means comprising an electrically conductive spring contactextending from one terminal of the battery penser'housing, the tubeextending from the cartridge to the clock motor' such that the springcontact engages the tube in deformation, an electrical conductorextending through the'tube from v the cartridge to the clock motor, anelectrically conductivedisc contact at the end of the tube adjacent tothe cartridge positioned to engage the other terminal of thebattery,spring means urging the disc contact into engagement with the othercontact of the battery, and means for connecting the conductor and thetube to the clock motor. 2. The system of claim 1, in which thecartridge has a'plurality of parallel vertical passages above the tubein which the tablets are stored in stacks, the passages being arrangedin a circle having a center aligned with the tube; v

the clock motor has an output shaft below the cartridge in spacedparallel relationship to the tube; and

the tablet dispensing means comprises a driving shaft with a bore thatfits around the tube so the driving shaft is rotatable thereabout, meansfor coupling the driving shaft to the output shaft of the clock motor, acrank extending from the driving shaft outwardly to end at the circle ofpassages, and a tablet dispensing foot mounted at the end of the crankbelow the cartridge to rotate along the circle of passages responsive tothe clock motor, the foot removing the tablet at the bottom of eachstack in turn as the foot rotates along the circle of passages.

3. A swimming pool chemical dispensing system comprising:

a cartridge having a body portion through which a plurality of parallelvertical passages are formed, the passages having bottom ends arrangedtolie along a given path, the cartridge including integral tabletretaining means in alignment with the bottom end of each passage forholding upthe corresponding stack such that the bottom tablet inthecorresponding stack lies completely below the body portion outside thepassage, and the second tablet from the bottom in the correspondingstack lies at least partially within the passage;

a stack of swimming pool chemical tablets stored in each passage, eachtablet being free tomove downward to replace the tablet below when suchtablet moves downward;

a dispenser housing'into which the cartridge removably fits from above;

tablet dispensing member within the dispenser housing, the member beingnormally disposed at the level of the bottom tablet in the stacks whenthe cartridge is positioned in the dispenser housing, being downwardlydepressible to a point under the bottom tablet in the stacks when themember lies under one of the stacks during insertion of the cartridgeinto the housing, and being returnable to the level of the bottom tabletin the stacks aftermovement of the member out from under said one stack;

and means within the dispenser housing for repeatedly moving thedispensing member along the given path to slide the bottom tablet ofeach stack in succession out of such stack for dispensing in a swimmingpool.

v 10 4. The system of claim 3, in which the tablet retaining means foreach passage comprises a first protrusion and a second protrusionextending toward each other in a direction transverse to the given path,the protrusions being spaced downwardly from the body portion of thecartridge a distance greater than the thickness of one tablet and lessthan the thickness of two tablets, and the foot moving means includes apost extending upwardly between the protrusions and means for attachingthe foot to the top of the post.

a 5. The system of claim 4, in which the foot extends transverse to thegiven path over one of the protrusions and the attaching means is ahinge connection between the foot and the post adapted to permit thefoot to slide between the protrusions when the cartridge is removed, thehinge connection being offset from the center of gravity of the foot sogravity tends to return the foot to a transverse position over one ofthe protrusions.

6. The system of claim 5, in which the moving means additionallycomprises a post support member below the cartridge having a bore inwhich the post slidably fits and spring means for urging the post in anupward direction.

7. The system of claim 6, in which the lower end of the post has abutton that prevents the post from sliding through the bore.

8. The system of claim 7, in which the passages of the cartridge arearranged in a circle around a central axis, the post support memberrotates about the central axis, and the given path is circular.

9. The system of claim 8, in which the cartridge has a bottom portioncomprising an inner ring disposed inside the circle of passages, theouter perimeter of the inner ring defining one wall of an annularchannel in which the foot rides, and an outer ring disposed outside thecircle of passages, the inner perimeter of the outer ring defining theother wall of the annular channel.

10. The system of claim 9, in which the protrusions are formed on theouter and inner rings, respectively.

11. A cartridge for a swimming pool chemical dispensing system having adispenser housing with a cavity into which the cartridge removably fitsand a dispensing assembly with a foot that moves through the cavity in agiven path, the cartridge comprising:

a body portion through which a plurality of parallel vertical passagesare formed, the passages having bottom ends arranged to lie along thegiven path;

a stack of swimming pool chemical tablets stored in each passage, eachtablet being free to move downward to replace the tablet below when suchtablet moves downward, the tablets having a sufficiently close fit intheir respective passages to axially align the tablets with theirrespective passages during movement; 7 bottom portion in which a channelis formed, the channel being slightly wider than the tablets andextending between the bottom ends of the passages along the given pathso the foot of the dispensing assembly can ride in the channels; andtablet retaining means in alignment with the bottom end of each passagefor holding up the corresponding stack such that the bottom tablet inthe stack lies completely below the body portion outside the passage andthe second tablet from the bottom in the stack lies at least partiallywithin the passage,

the bottom tablet in the stacks being free to drop away from thecartridge when pushed between suc- 1 1 cessive retaining means by thefoot of the dispensing assembly.

12. The cartridge of claim 11, in which the tablet retaining means holdsup the bottom tablet in each stack in axial alignment with thecorresponding passage.

13. The cartridge of claim 12, in which the passages through the bodyare arranged so their bottom ends lie in a circle.

14. The cartridge of claim 11, in which the bottom portion comprises aninner ring disposed inside the circle of passages, the outer perimeterof the inner ring defining one wall of the channel, and an outer ringdisposed outside the circle of passages, the inner perimeter of theouter ring defining the other wall of the channel.

15. The cartridge of claim 14, in which the tablet retaining means eachcomprise an inward protrusion from the outer ring and an outwardprotrusion from the inner ring, the inner and outer protrusions beingspaced from the body portions a distance greater than the thickness ofone tablet and less than the thickness of two tablets.

16. The cartridge of claim 15, in which the leading edge of one of theprotrusions of each tablet retaining means has a tablet retaining nippleextending upwardly toward the body portion, and the other protrusion ofeach tablet retaining means presents a smooth upper surface for movementof the dispensing foot thereacross.

17. The cartridge of claim 16, in which the body portion has a verticalcentral passage lying inside the circle of passages, and a battery forenergizing the dispensing assembly disposed in the central passage.

18. A swimming pool water retardant dispensing system comprising:

a cartridge for storing tablets of the water retardant,

the cartridge having a plurality of passages disposed in parallelrelationship about a central axis;

a stack of water retardant tablets disposed in each passage of thecartridge;

a dispenser housing into which the cartridge removably fits from abovesuch that the central axis of the cartridge is vertically oriented, thehousing having a vertical opening between the bottom of the cartridgeand an exit designed to lie above the water surface of the swimmingpool;

a motor disposed in the vertical opening of the dispenser housingunderneath the cartridge in alignment with its central axis to definewith the housing an annular passageway between the cartridge and theexit; and

means responsive to the motor for sequentially freeing the tablet at thebottom of each stack to fall through the passageway to the exit.

19. The system of claim 18, in which the motor has a generallycylindrical shape with a periphery that extends away from the centralaxis of the cartridge at least as far as the passages in the cartridgeand the housing has a downwardly and outwardly slanted shield lying inthe vertical passageway between the cartridge and motor so as to deflecttablets falling from the cartridge outwardly from the motor.

20. The system of claim 18, in which the dispenser housing has an innerfunnel shaped bottom portion with a first opening larger that thetablets near its apex and an outer funnel shaped bottom portion with asecond opening larger that the tablets near its apex, the

12 first and second openings of the funnels defining the exit.

21. The system of claim 20, in which the openings of the bottom portionshave axes that are laterally offset relative to each other.

22. The system of claim 21, in which the axis of the second opening isaligned with the central axis of the cartridge and the axis of the firstopening is laterally offset from the central axis of the cartridge.

23. The system of claim 22, in which a plurality of small holes forwater vapor escape are formed in the outer bottom portion.

24. A swimming pool chemical dispensing system comprising:

a dispensing unit having a central axis along which tablets of aswimming pool chemical are adpated to fall to an exit point lying abovethe water surface of the swimming pool;

a bracket having a stopping surface and being adapted to be attached tothe edge of the swimming pool;

means for pivotally mounting the dispenser unit to the bracket so thatthe dispensing unit is free to rotate until it abuts the stoppingsurface, the stopping surface being oriented so the central axis of thedis-. pensing unit is vertical when the dispensing unit abuts thestopping surface; and

means for securing the dispensing unit against rotation.

25. The system of claim 24, in which the bracket comprises a flexiblestrip fixed to the edge of the swimming pool, a lower angular memberhaving a first vertical portion abutting the edge of the pool and asecond horizontal portion abutting and fixed to the flexible strip, anupper angular member having a first horizontal portion abutting thesecond portion of the lower member and a second vertical portionextending upwardly from the first portion, and means for adjustablyattaching the first portion of the upper member to the second portion ofthe lower member such that the second portion of the upper member can beextended toward and retracted from the pool edge; the dispenser unit hasadjacent to the bracket a guiding surface parallel to the central axis;and the mounting means connects the dispenser unit to the second portionof the upper member so the dispenser unit is free to rotate until itsguiding surface abuts the first portion of the bottom member.

26. A water evaporation retardant dispensing system comprising:

a cartridge having a body portion through which a plurality of parallelvertical passages are formed;

a stack of disc-shaped water evaporation retardant tablets stored ineach passage, each tablet being free to move downward to replace thetablet below when such tablet moves downward;

a dispenser housing into which the cartridge removably fits;

means for attaching the housing to the edge of a swimming pool;

a motor in the housing having an output shaft that rotates at a slowrelatively constant speed without interruption over predeterminedperiods of time; and

a tablet dispensing mechanism in the housing, the tablet dispensingmechanism sequentially removing tablets from the bottom of each stack inturn and dispensing such tablets into the pool responsive to the motorat a rate proportional to the speed of rotation of the output shaft.

27. A swimming pool chemical dispensing system comprising:

a cartridge having a body portion through which a plurality of parallelvertical passages are formed, the passages having bottom ends arrangedto lie along a given path;

. a stack of swimming pool chemical tablets stored in each passage, eachtablet being free to move downward to replace the tablet below when suchtablet moves downward;

tablet retaining means in alignment with the bottom end of each passagefor holding up the corresponding stack such that the bottom tablet inthe corresponding stack lies completely below the body portion outsidethe passage, and the second tablet from the bottom in the correspondingstack lies at least partially within the passage;

a dispenser housing into which the cartridge removably fits from above;

a tablet dispensing foot within the dispenser housing, the foot beingdisposed at the level of the bottom tablet in the stacks when thecartridge is positioned in the dispenser housing;

means within the dispenser housing for repeatedly moving the dispensingfoot along the given path to slide the bottom tablet of each stack insuccession 14 out of such stack for dispensing in a swimming pool; and

means for disengaging the tablet dispensing foot from the tabletretaining means when the foot lies under one of the stacks duringremoval of the cartridge from the housing.

28. The system of claim 27, in which the tablet retaining means for eachpassage comprises a first protrusion and a second protrusion extendingtoward each other in a direction-transverse to the given path, theprotrusions being spaced downwardly from the body portion of thecartridge a distance greater than the thickness of one tablet and lessthan the thickness of two tablets, the foot moving means includes a postextending upwardly between the protrusions, the foot extends transverseto the given path over one of the protrusions, and the foot disengagingmeans comprises a hinge connection between the foot and the postadaptedto pivot so the foot slides between the protrusions when thecartridge is removed.

29. The system of claim 27, in which the tablet dispensing foot isdownwardly depressible when the foot lies under one of the stacks duringinsertion of the cartridge into the housing.

30. The system of claim 3, in which the tablet dispensing member'isspring loaded to return the member to the level of the bottom tabletafter movement of the member out from under said one stack.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent NO. 5 7Dated November 11, 1975 Inventor(s) John J. Rowlette Page 1 of 3 It iscertified that error appears in the above-identified patent and thatsaid Letters Patent are hereby corrected as shown below:

Columns 5 through 8 as shown on the attached pages should be included,but will apply to the grant only.

Signed and Scaled this tenth Day of February 1976 [SEAL] Arrest:

RUTH C. MASON C. MARSHALL DANN Allesting Ojficer Commissioner of Patentsand Trademarks As described in more detail below in connection with HO.5. assembly 59 carries tablet dispensing foot 68. As assembly 59rotates. foot 68 traverses channel 30 and pushes the bottom tablet ineach of stacks in turn along channel until such tablet is clear of thecorresponding protrusions 27 and 28. where it is free to fall. While thebottom tablet in one ofstacks 20 is being pushed along channel 30. thesecond tablet from the bottom is held in place by the walls of thecorrespond ing passage 16. After the bottom tablet is clear ofprotrusions 27 and 28 and is thereby dispensed. the second tablet fromthe bottom slides down against protrusions 27 aand 28 to replace it. Inthis manner. the tablets stored in cartridge 11 are sequentiallydispensed one by one as assembly 59 rotates and foot 68 traverses agiven path, which is circular. The dispensed tablets fall by virtue ofgravity until they hit shield 43 and are deflected outwardly to avoidclock motor 50.

On the bottom of body 36 are mounted an inner funnel 69 and an outerfunnel 70. Funnel 70 is secured to the bottom of body 36 by fasteners71, and funnel 69 is clamped between funnel 70 and the bottom of body36. Funnel 69 has a hole 72 drilled along an axis parallel to and spacedfrom axis 13. and funnel 70 has a hole 73 drilled along an axiscoinciding with axis 13. Holes 72 and 73, which serve as the exit fromthe dispensing system, are large enough to permit the tablets to passwithout difficulty. After the dispensed tablets are deflected outwardlyby shield 43. they fall freely through the annular region around clockmotor until they are deflected by the inwardly and downwardly slopingsurface offunncl 69. At the bottom of funnel 69, the tablets fallthrough hole 72, fall through hole 73, and drop into the water belowdispenser housing 10.

Holes 72 and 73 are intentionally misaligned to minimize the upward flowofwater vapor into the interior of body 36. A plurality of small holes74 are drilled through funnel to permit trapped water vapor to escapefrom the region between funnels 69 and 70. lf too much water vaporenters the interior of body 36 despite these measures. so the tabletsbecome moist enough to impair their dispensabihty. more elaboratemeasures can be taken. For example. silica gel could be placed in thefree space of passage 15 lying above battery 24; or a combination ofchemicals that give off ammonia when exposed to water vapor could beplaced inside body 36 below cartridge 11. so the lighter ammoniaoccupies the interior of body 36 where it is effectively trapped andthus prevents the upward movement of the water vapor through holes 72and 73.

Reference is made to FIG. 4 for a detailed description of post assembly55. The bottom of a hollow elec trically conductive tube fits in bore56, where it is secured to plate 51 by cement. By way ofexample, tube 80could be rendered electrically conductive by nickelplating its outersurface. or it could be made from a conductive material and optionallynickel-plated to reduce corrosion. A spring retaining ring 81 is securedinside tube 80 by cement. .-\n electrically insulativc disc 32 isattached to an electrically conductive disc 83 by cement. By way ofexample. disc 83 could be pure nickel. An insulat'cd flexible electricalconductor 84 extends through the interior of tube 80. At one end.conductor 84 is electrically connected to the side ofdisc 83 facing disc32. At the other end. conductor 84 is electrically connected toconductor 57a The outer surface of tube 80 is electrically connected toconductor 57b. A compression spring 85 extends between retaining ring 8iand disc 82. Buttery 21. positive terminal 22. and contact 23 ofcartridge II are shown in their positions relative to post assembly 55,as cartridge H is about to be placed in dispenser housing l0. Ascartridge 11. which is not shown in H6. 4, moves downardly. terminal 22contacts disc 83 and contact 23 engages the outside surface of tube 80.As depicted by the arrows. battery 21 moves downward. disc 83 mo esdownward, and contact 23 moves outward until cartridgc 11 bottomsagainst ring 39 (H6. 1). At such time. discs 82 and 83 are spaced fromthe end of tube 80, thereby providng leeway for variations in theposition of battery 21. The force of spring 85 insures that goodelectrical contact is maintained from positive terminal 22 through disc83 and conductor 84 to conductor 57a. By virtue of its flexibility. theexcess length of conductor 84 coils within tube 80. The outwarddeformation of contact 23 which is caused by its engagement with theouter surface of tube 80, insures that good electrical contact ismaintained from negative terminal 24 through tube 80 to conductor 571:.To improve the corrosion resistance of the electrical connection. theend of contact 23 engaging the outer surface of tube 80 could be platedwith nickel.

Reference is made to FIGS. 3, 5, 5A. and 5B for a detailed descriptionof tablet dispensing assembly 59. Bore 60 is formed in a central shaftportion 86. A. the upper end of shaft portion 86, a crank portion 87extends radially outward. A post 88 fits slidably in a bore 89 at theend of crank portion 87. The diameter of post 88 is smaller than thespace between protrusions 27 and 28. A button 90 is formed on the lowerend of post 88 as a stop to prevent it from sliding upwardly out of bore89. A leaf spring 91. which is secured to cran portion 87 by a rivet 92,engages a slot in button 90 and urges post 88 in an upward direction.Also. rotation of post 88 is prevented by this engagement. Tabletdispensing foot 68 is attached to the upper end of post 88 by a hinge 93(FIG. 5A). Foot 68 is free to rotate about hinge 93 in a clockwisedirection. from its position as viewed in PK]. 5. A lower surface 94 offoot 68 is shaped to limit the extent of rotation of foot 68. In HO. 5foot 68 is represented at the counterclockwise limit ofits rotationalpath. ln FlG. 58, foot 68 is represented at the clockwise limit of itsrotational path. Thus. surface 94 and the adjacent surface of post 88function as a cam and a cam follower to limit the rotation of foot 68.The center of gravity of foot 68 lies to the left of hinge 93. as viewin H0. 5, so gravity urges foot 68 in a counterclockwise direction tothe position depicted in FIG. 5.

If dispenser assembly 59 happens to be oriented so foot 63 lies betweenadjacent stacks 20 when cartridge 11 is inserted into dispenser housing10. foot 68 immediately moves up into channel 30 at the level ofthebottom tablets. as shown in FIG. 1. ln this position. button 90 abutsthe bottom ofcrank portion 87 and the t p of foot 63 lies below thesecond tablet from the bottom of the stack. However. if dispenserassembly 59 happens to be oriented so foot 68 lies'under one of stacks20 when cartridge 11 is inserted into dispenser housing 10. protrusions27 and 28 prevent foot 68 from moving upward to thclevel of the bottomtablets. in such cases, cartridge 11 depresses foot 63 downwardly topush post 88 in opposition to the force of spring 91, where is remainsuntil assembly 59 rotates sufficiently for foot 68 to be clear ofprotrusions 27 and 28; then the force of spring 91 urges post 88upwardly until button 90 abuts Page of 5 the bottom of crank portion 87and foot 68 assumes a position at the level of the bottom tablets.

If dispenser assembly 59 happens to be oriented so foot 68 lies betweenadjacent stacks when cartridge 11 is removed from dispenser housing 10,foot 8 is disengaged from channel without touching cartridge 11.However, if dispenser assembly 5) happens to be oriented foot 68 liesunder one of stacks 20 when cartridge 11 is removed, foot 68 contactsprotrusion 27 as cartridge 11 is removed. Since foot 68 is free torotate in a clockwise direction, it slips out of the space betweenprotrusions 27 and 23 and is thereby disengaged from channel 30 withoutbeing damaged.

Since the force ofgravity is used to deliver the tablets from cartridgell to the water, it is important that dispenser housing 10 be orientedso axis l3 is approximately vertical. A universal bracket assemblyillustrated in FIGS. 6 and 7 permits dispenser housing 10 to be mountedvertically at pool edges whether the mounting surface is flat or is anyof the variety of bull nose copings with different shapes. A lowerangular member is secured by cement and by two fasteners 101 to aflexible strip 102, which is, in turn, secured by cement to the edge ofthe swimming pool represented at 103. Fasteners 101 each have a headrecessed in strip 102 and are fixed against rotation. For example,member 100 can be made of stainless steel, and a cloth re-inforcedneoprene rubber strip could be used for member 102 to provide thedesired flex without stretching so much that bracket 100 would tipforward under the weight of dispenser housing 10. A portion 100a abutsthe upright side of the pool and a portion 10Gb lies above the coping.An upper angular member 204 has a portion 104 a t .11. abuts portion190b, and is fastened to it by. two finger nuts 105, which screw ontofasteners 101. Member 104 also has a portion l04b from which verticalhinge mounting plate portions 104a extend. Portion 104a has slots 106that permit the posi tion of member 104 to be adjusted toward or awayfrom the pool edge relative to member 100. Hinge mounting plate portions104: are spaced apart just enough to fit between hinge mountingprotrusions 33 of body 36. Plate portions He and protrusions 33 arejoined by fasteners 107, which serve as hinge points, allowing dispenserhousing 10 to rotate. Thus dispenser housing 10 rotates in a clockwisedirection, as viewed in FIG. 6, until protrusions 33 abut portion 100a.Member 104 is adjusted relative to member 100 until orienting sidesurfaces 32 are flush with portion 100a. When this adjustment is made,axis .13 ofdispenser housing 10 is vertical, assuming that portion a ofmember 100 is exactly vertical. If this is not the case, then member 104is adjusted accordingly relative to member 100, so dispenser housing l!)is vertically oriented. Dispenser housing 10 is free to rotate in eitherdirection, as viewed in H6. 6, in order to accomplish this adjustment.

The described swimming pool chemical dispensing system is designed toaccommodate expendable tablet storage cartridges, i.e., cartridge 11.Thus, for example, one cartridge could carry a one monthv supply oftablets and a battery having sufficient electrical energy storagecapacity to energize the dispenser actuating motor, i.e., clock motor50, for a comparable period of time. Each month, the litl is taken oft;the used cartridge is removed upwardly from the dispenser housing,thrown away, and replaced from above with a new cartridge; and the lidis put back on. As the new cartridge is placed in the dispenser housing,the electrical connection between the battery in the cartridge and themotor in the dispenser housing is automatically established in themanner described above in connection with FIG. 4. Similarly, the tabletdispensing mechanism, i.e., foot 68, is automatically positioned at thelevel of the bottom tablet of each stack in the new cartridge, i.e.,positioncd in channel 30, in the manner described above in connectionwith H6. 5. Thereafter, the motor drives the actuating mechanism inresponse to the energy from the battery so the tablets are dispensedsequentially one at a time over the period of a month. When thecartridge is removed at the end of the month, the electrical connectionfrom the battery to the motor is automatically interrupted and thetablet actuating mechanism is disengaged from the cartridge withoutdamage to the components of dispenser housing 10.

The described embodiment of the invention is only considered to bepreferred and illustrative of the inventive concept; the scope of theinvention is not to be restricted to such embodiment. Various andnumerous other arrangements may be devised by one skilled in the artwithout departing from the spirit and scope of this invention. Forexample, it may be desirable to automatically disconnect clock 50 duringcertain times. it has been found that during periods of time in whichthe pool is not being used, such as at night, less frequent applicationsof water retardant are required to maintain an effective retarding layeron the water surface. Therefore, it would usually be desirable todisconnect clock 50 at night. This could be done by means of a photocellactuated electrical circuit that switches off clock 50 when the sun goesdown, and switches on clock 50 when the sun comes up. Alternatively,this could be done by a gear train between assembly 59 and shaft 53which disengages during part of each day. e.g.. every other completerevolution of shaft 53. Furthermore, the stacks of tablets in thecartridge could be arranged differently, e.g., in rows, in which casethe given path that the tablet dispensing foot traverses would not becircular. While mounting the battery in the cartridge is most convenientfor the user, it would also be possible to design the dispenser with thebattery in the dis penser, rather than in the cartridge. Further, thetablets could take many sizes and shapes, including what are sometimesregarded as briquettes or peilets, or in general solid compact units.

What is claimed is:

l. A swimming pool chemical dispensing system comprising:

a cartridge for storing tablets of a swimming pool chemical; a dispenserhousing into which the cartridge removably fits; means for attaching thehousing to the edge of a swimming pool;

a battery having a positive terminal and a negative terminal disposed inthe cartridge;

means disposed in the housing including an electrical clock motor fordispensing tablets stored in the cartridge into the swimming poolresponsive to the power source; and

means operable when the cartridge is positioned in the housing fortransmitting power from the source to the dispensing means to dispensetablets stored in the cartridge, the power transmitting means comprisingan electrically conductive spring contact extending from one terminal ofthe battery

1. A swimming pool chemical dispensing system comprising: a cartridgefor storing tablets of a swimming pool chemical; a dispenser housinginto which the cartridge removably fits; means for attaching the housingto the edge of a swimming pool; a battery having a positive terminal anda negative terminal disposed in the cartridge; means disposed in thehousing including an electrical clock motor for dispensing tabletsstored in the cartridge into the swimming pool responsive to the powersource; and means operable when the cartridge is positioned in thehousing for transmitting power from the source to the dispensing meansto dispense tablets stored in the cartridge, the power transmittingmeans comprising an electrically conductive spring contact extendingfrom one terminal of the battery to a point at the periphery of thecartridge, an electrically conductive hollow tube mounted in thedispenser housing, the tube extending from the cartridge to the clockmotor such that the spring contact engages the tube in deformation, anelectrical conductor extending through the tube from the cartridge tothe clock motor, an electrically conductive disc contact at the end ofthe tube adjacent to the cartridge positioned to engage the otherterminal of the battery, spring means urging the disc contact intoengagement with the other contact of the battery, and means forconnecting the conductor and the tube to the clock motor.
 2. The systemof claim 1, in which the cartridge has a plurality of parallel verticalpassages above the tube in which the tablets are stored in stacks, thepassages being arranged in a circle having a center aligned with thetube; the clock motor has an output shaft below the cartridge in spacedparallel relationship to the tube; and the tablet dispensing meanscomprises a driving shaft with a bore that fits around the tube so thedriving shaft is rotatable thereabout, means for coupling the drivingshaft to the output shaft of the clock motor, a crank extending from thedriving shaft outwardly to end at the circle of passages, and a tabletdispensing foot mounted at the end of the crank below the cartridge torotate along the circle of passages responsive to the clock motor, thefoot removing the tablet at the bottom of each stack in turn as the footrotates along the circle of passages.
 3. A swimming pool chemicaldispensing system comprising: a cartridge having a body portion throughwhich a plurality of parallel vertical passages are formed, the passageshaving bottom ends arranged to lie along a given path, the cartridgeincluding integral tablet retaining means in alignment with the bottomend of each passage for holding up the corresponding stack such that thebottom tablet in the corresponding stack lies completely below the bodyportion outside the passage, and the second tablet from the bottom inthe corresponding stack lies at least partially within the passage; astack of swimming pool chemical tablets stored in each passage, eachtablet being free to move downward to replace the tablet below when suchtablet moves downward; a dispenser housing into which the cartridgeremovably fits from above; a tablet dispensing member within thedispenser housing, the member being normally disposed at the level ofthe bottom tablet in the stacks when the cartridge is positioned in thedispenser housing, being downwardly depressible to a point under thebottom tablet in the stacks when the member lies under one of the stacksduring insertion of the cartridge into the housing, and being returnableto the level of the bottom tablet in the stacks after movement of themember out from under said one stack; and means within the dispenserhousing for repeatedly moving the dispensing member along the given pathto slide the bottom tablet of each stack in succession out of such stackfor dispensing in a swimming pool.
 4. The system of claim 3, in whichthe tablet retaining means for each passage comprises a first protrusionand a second protrusion extending toward each other in a directiontransverse to the given path, the protrusions being spaced downwardlyfrom the body portion of the cartridge a distance greater than thethickness of one tablet and less than the thickness of two tablets, andthe foot moving means includes a post extending upwardly between theprotrusions and means for attaching the foot to the top of the post. 5.The system of claim 4, in which the foot extends transverse to the givenpath over one of the protrusions and the attaching means is a hingeconnection between the foot and the post adapted to permit the foot toslide between the protrusions when the cartridge is removed, the hingeconnection being offset from the center of gravity of the foot sogravity tends to return the foot to a transverse position over one ofthe protrusions.
 6. The system of claim 5, in which the moving meansadditionally comprises a post support member below the cartridge havinga bore in which the post slidably fits and spring means for urging thepost in an upward direction.
 7. The system of claim 6, in which thelower end of the post has a button that prevents the post from slidingthrough the bore.
 8. The system of claim 7, in which the passages of thecartridge are arranged in a circle around a central axis, the postsupport member rotates about the central axis, and the given path iscircular.
 9. The system of claim 8, in which the cartridge has a bottomportion comprising an inner ring disposed inside the circle of passages,the outer perimeter of the inner ring defining one wall of an annularchannel in which the foot rides, and an outer ring disposed outside thecircle of passages, the inner perimeter of the outer ring defining theother wall of the annular channel.
 10. The system of claim 9, in whichthe protrusions are formed on the outer and inner rings, respectively.11. A cartridge for a swimming pool chemical dispensing system having adispenser housing with a cavity into which the cartridge removably fitsand a dispensing assembly with a foot that moves through the cavity in agiven path, the cartridge comprising: a body portion through which aplurality of parallel vertical passages are formed, the passages havingbottom ends arranged to lie along the given path; a stack of swimmingpool chemical tablets stored in each passage, each tablet being free tomove downward to replace the tablet below when such tablet movesdownward, the tablets having a sufficiently close fit in theirrespective passages to axially align the tablets with their respectivepassages during movement; a bottom portion in which a channel is formed,the channel being slightly wider than the tablets and extending betweenthe bottom ends of the passages along the given path so the foot of thedispensing assembly can ride in the channels; and tablet retaining meansin alignment with the bottom end of each passage for holding up thecOrresponding stack such that the bottom tablet in the stack liescompletely below the body portion outside the passage and the secondtablet from the bottom in the stack lies at least partially within thepassage, the bottom tablet in the stacks being free to drop away fromthe cartridge when pushed between successive retaining means by the footof the dispensing assembly.
 12. The cartridge of claim 11, in which thetablet retaining means holds up the bottom tablet in each stack in axialalignment with the corresponding passage.
 13. The cartridge of claim 12,in which the passages through the body are arranged so their bottom endslie in a circle.
 14. The cartridge of claim 11, in which the bottomportion comprises an inner ring disposed inside the circle of passages,the outer perimeter of the inner ring defining one wall of the channel,and an outer ring disposed outside the circle of passages, the innerperimeter of the outer ring defining the other wall of the channel. 15.The cartridge of claim 14, in which the tablet retaining means eachcomprise an inward protrusion from the outer ring and an outwardprotrusion from the inner ring, the inner and outer protrusions beingspaced from the body portions a distance greater than the thickness ofone tablet and less than the thickness of two tablets.
 16. The cartridgeof claim 15, in which the leading edge of one of the protrusions of eachtablet retaining means has a tablet retaining nipple extending upwardlytoward the body portion, and the other protrusion of each tabletretaining means presents a smooth upper surface for movement of thedispensing foot thereacross.
 17. The cartridge of claim 16, in which thebody portion has a vertical central passage lying inside the circle ofpassages, and a battery for energizing the dispensing assembly disposedin the central passage.
 18. A swimming pool water retardant dispensingsystem comprising: a cartridge for storing tablets of the waterretardant, the cartridge having a plurality of passages disposed inparallel relationship about a central axis; a stack of water retardanttablets disposed in each passage of the cartridge; a dispenser housinginto which the cartridge removably fits from above such that the centralaxis of the cartridge is vertically oriented, the housing having avertical opening between the bottom of the cartridge and an exitdesigned to lie above the water surface of the swimming pool; a motordisposed in the vertical opening of the dispenser housing underneath thecartridge in alignment with its central axis to define with the housingan annular passageway between the cartridge and the exit; and meansresponsive to the motor for sequentially freeing the tablet at thebottom of each stack to fall through the passageway to the exit.
 19. Thesystem of claim 18, in which the motor has a generally cylindrical shapewith a periphery that extends away from the central axis of thecartridge at least as far as the passages in the cartridge and thehousing has a downwardly and outwardly slanted shield lying in thevertical passageway between the cartridge and motor so as to deflecttablets falling from the cartridge outwardly from the motor.
 20. Thesystem of claim 18, in which the dispenser housing has an inner funnelshaped bottom portion with a first opening larger that the tablets nearits apex and an outer funnel shaped bottom portion with a second openinglarger that the tablets near its apex, the first and second openings ofthe funnels defining the exit.
 21. The system of claim 20, in which theopenings of the bottom portions have axes that are laterally offsetrelative to each other.
 22. The system of claim 21, in which the axis ofthe second opening is aligned with the central axis of the cartridge andthe axis of the first opening is laterally offset from the central axisof the cartridge.
 23. The system of claim 22, in which a plurality ofsmall holes for water vapor eScape are formed in the outer bottomportion.
 24. A swimming pool chemical dispensing system comprising: adispensing unit having a central axis along which tablets of a swimmingpool chemical are adpated to fall to an exit point lying above the watersurface of the swimming pool; a bracket having a stopping surface andbeing adapted to be attached to the edge of the swimming pool; means forpivotally mounting the dispenser unit to the bracket so that thedispensing unit is free to rotate until it abuts the stopping surface,the stopping surface being oriented so the central axis of thedispensing unit is vertical when the dispensing unit abuts the stoppingsurface; and means for securing the dispensing unit against rotation.25. The system of claim 24, in which the bracket comprises a flexiblestrip fixed to the edge of the swimming pool, a lower angular memberhaving a first vertical portion abutting the edge of the pool and asecond horizontal portion abutting and fixed to the flexible strip, anupper angular member having a first horizontal portion abutting thesecond portion of the lower member and a second vertical portionextending upwardly from the first portion, and means for adjustablyattaching the first portion of the upper member to the second portion ofthe lower member such that the second portion of the upper member can beextended toward and retracted from the pool edge; the dispenser unit hasadjacent to the bracket a guiding surface parallel to the central axis;and the mounting means connects the dispenser unit to the second portionof the upper member so the dispenser unit is free to rotate until itsguiding surface abuts the first portion of the bottom member.
 26. Awater evaporation retardant dispensing system comprising: a cartridgehaving a body portion through which a plurality of parallel verticalpassages are formed; a stack of disc-shaped water evaporation retardanttablets stored in each passage, each tablet being free to move downwardto replace the tablet below when such tablet moves downward; a dispenserhousing into which the cartridge removably fits; means for attaching thehousing to the edge of a swimming pool; a motor in the housing having anoutput shaft that rotates at a slow relatively constant speed withoutinterruption over predetermined periods of time; and a tablet dispensingmechanism in the housing, the tablet dispensing mechanism sequentiallyremoving tablets from the bottom of each stack in turn and dispensingsuch tablets into the pool responsive to the motor at a rateproportional to the speed of rotation of the output shaft.
 27. Aswimming pool chemical dispensing system comprising: a cartridge havinga body portion through which a plurality of parallel vertical passagesare formed, the passages having bottom ends arranged to lie along agiven path; a stack of swimming pool chemical tablets stored in eachpassage, each tablet being free to move downward to replace the tabletbelow when such tablet moves downward; tablet retaining means inalignment with the bottom end of each passage for holding up thecorresponding stack such that the bottom tablet in the correspondingstack lies completely below the body portion outside the passage, andthe second tablet from the bottom in the corresponding stack lies atleast partially within the passage; a dispenser housing into which thecartridge removably fits from above; a tablet dispensing foot within thedispenser housing, the foot being disposed at the level of the bottomtablet in the stacks when the cartridge is positioned in the dispenserhousing; means within the dispenser housing for repeatedly moving thedispensing foot along the given path to slide the bottom tablet of eachstack in succession out of such stack for dispensing in a swimming pool;and means for disengaging the tablet dispensing foot from the tabletretaining means when the foot lies under one of the stacks duringremoval of the cartridge from the housing.
 28. The system of claim 27,in which the tablet retaining means for each passage comprises a firstprotrusion and a second protrusion extending toward each other in adirection transverse to the given path, the protrusions being spaceddownwardly from the body portion of the cartridge a distance greaterthan the thickness of one tablet and less than the thickness of twotablets, the foot moving means includes a post extending upwardlybetween the protrusions, the foot extends transverse to the given pathover one of the protrusions, and the foot disengaging means comprises ahinge connection between the foot and the post adapted to pivot so thefoot slides between the protrusions when the cartridge is removed. 29.The system of claim 27, in which the tablet dispensing foot isdownwardly depressible when the foot lies under one of the stacks duringinsertion of the cartridge into the housing.
 30. The system of claim 3,in which the tablet dispensing member is spring loaded to return themember to the level of the bottom tablet after movement of the memberout from under said one stack.